Geiger Counter

Thank you for purchasing the Geiger Counter. Welcome to the world of digital distruction.

The Geiger Counter is a bit-crushing distortion and waveshaper. Your signal passes through an analog preamp with Gain and Tone controls, then into a digital heart that re-samples it, reduces its bit depth, and reshapes it through one of many wave tables. In the Eurorack version every parameter is available for CV modulation, and the module is fully DC coupled so it will process audio and control voltage alike.

Use a 16 pin to 10 pin ribbon cable for installation. +12 volts is towards the top of the module. The Geiger Counter uses up to 60mA at +/-12 volts. Plug in the ribbon cable and then secure the module using four M3x6 mm screws. The cable should have the red stripe pointing down on both the module and on standard Doepfer style racks.

Low settings provide clean tones with no distortion at all, while high settings will brickwall your signal for great sustain. Use the Gain control as a coarse setting for getting the desired tone from the selected wave table.

This switch removes the tone control from the preamp circuit. When down, the tone control sucks some volume from the gain, and this allows the pure ultra hot signal to go directly into the Wave Table. If a very clean tone is desired, set to Disable and adjust the gain to get the right amount of breakup. For most wave tables, disabling the Tone will produce completely different sounds by brickwalling to the extremes of the tables faster.

The Geiger Counter's tone control blends muffled low-mids with chimey and clear upper mids and highs, providing a very large range of sounds in junction with the Gain. All the way down and the sound is muffled and grungy with little upper harmonic content. The middle range is smooth and full bodied. The top range cuts the lows completely for only upper harmonic content. Use the Tone to fine tune the sound of the wave table.

Direct Input bypasses the preamp. The Geiger is DC coupled from this point on, so it will pass control voltages as well as audio into the digital section.

This control attenuates the level coming out of the preamp to add or remove hard clipping going into the digital section of the Geiger Counter.

Controls the length of the samples your signal is converted into. Full up and the Geiger Counter samples faster than a CD. Dial it down a little and you'll lower the fidelity and frequency response, adding overtones and difference frequencies. Down a little produces some very nice chimey clean tones. Down more and higher notes disappear into chaos, all the way down to 240Hz. The LED when RED indicates that the range is reduced to the upper part.

The Sample Rate CV input and CV Level control take standard control voltages to modulate the Sample Rate. When a cable is inserted, the Sample Rate knob on the right is used to set the center frequency about which the CV signal modulates. When the LED is GREEN, the CV signal is logically ANDed to the Sample Rate knob setting.

Reduces the vertical fidelity of your signal. This introduces quantization errors that create distortion. When the LED is GREEN, your signal is MASKed by the Bit Depth setting: this creates vertical gaps in the signal, introducing uneven quantization errors, adds lots of distortion, but can be used to clean up noise and tone shape. When the LED is RED, the Bit Depth operation occurs before the Wave Table modulation; this allows you to tone shape the response of the Wave Table.

The Bit Depth CV and Wave Table CV inputs and CV Level controls take standard control voltages to modulate the Bit Depth and the Wave Table controls. When a cable is inserted, the Bit Depth and Wave Table knobs control the center frequency at which the CV modulates around.

The display and rotary encoder control the wave table setting. The Wave Table is like high-school algebra applied to your signal, running it through a math function adding distortion, gain, harmonics and mayhem. The more vertical action in each wave table, the more harmonics are produced. The signal is at rest in the middle, horizontally on each image.

Out and Level output the final signal at +/-5Vpp. The Level control reduces the volume of the Output.

This trim pot sets the CV bias. To set, turn the Wave Table CV Level and the Output Level knobs down. Plug a patch cable between the Wave Table CV and the Output. Turn the trim pot until the Wave Table reads 80. This is calibrated at the factory.

On the back of the Geiger near the power connector is a blue trim pot. This adjusts the DC offset of the output stage. It should be set AFTER the input bias pot, with no signal, Direct In level all down, and output level all up, to 0.00VDC. This is calibrated at the factory.

WMD is located in Denver, CO. Reach us by phone at 303-549-9205 or by email at sales@wmdevices.com. For more on the Geiger Counter, including video demos, visit the product page.